Tobacco, green peppers, tomatoes, cucumbers and watermelons, and the like, which are cultivated in the field, in the paddy field and in greenhouses, are often damaged by tobacco mosaic virus (hereinafter referred to as TMV), cucumber mosaic virus, cucumber green-spot mosaic virus and potato Y virus, etc.
These viruses also exist in other crops, such as weeds, seeds and seedlings and in soil. They are contagious and are often carried by juice sucking insects, and the like.
Previously, soil disinfection and insecticides were used as countermeasures for plant protection and removal of crop viruses. These countermeasures, however, were mainly an indirect means of protection and technical methods of virus removal.
There are a few direct plant protection and virus removal chemicals which are called "sodium alginic acid" (Japan Patent No. 717594, the Ministry of Agriculture, Forestry and Fisheries Registered No. 13440) and culture extract of Lentinus edodes (Japan Patent No. 1012014, the Ministry of Agriculture Forestry and Fisheries Registered No. 15584). However, neither of these effect systemically; therefore, they are incapable of moistening the entire plant, and it is necessary to scatter them all over the plant. In addition, their effectiveness in the field is not very high.
On the other hand, protein, which is found in the marvel-of-Peru, has recently been popularized as an anti-viral plant substance which has actually systemic effectiveness [Japan TOKKYO-KOKAI-KOHO (18-month Publication of Unexamined Patent Application) SHOWA 60(1985)-243100 (hereinafter referred to as TOKKAISHO 60-243100)]. Unfortunately, however, production of this protein must comply with agricultural means or plant cell culture [Japan TOKKAISHO 61(1986)-5790]. Therefore, productivity is automatically limited, and it is impossible to provide it at low cost for mass production.
The present invention has improved on defects of the previous plant protection and virus removal chemicals on the market. The present invention has achieved more effective saturated shifting dominance, and a secure and valid chemical substance can be provided at low cost for mass production.